• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.8
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• pp.37-44
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• 2004

This paper describes a new GaAs-based surface-micromachined microstrip line supported by dielectric post and air-gapped signal line with ground metal. This new type of dielectric-supported air-gapped microstripline(DAML) structure is developed using surface micromachining techniques to provide easy means of airbridge connection between the signal lines and to archive low losses at millimeter-wave frequency band with wide impedance range. Each DAMLs with the length of 5 mm are fabricated and the measured characteristics are compared with those of the conventional microstrip transmission line. These transmission lines are composed of 10 ${\mu}{\textrm}{m}$ height of signal line, post size of 10 ${\mu}{\textrm}{m}$ ${\times}$ 10 ${\mu}{\textrm}{m}$ and post height of 9 ${\mu}{\textrm}{m}$. By elevating the signal lines from the substrate using the micromachining technology, the substrate dielectric loss can be reduced Compared with of the conventional microstrip transmission line showing 7.5 dB/cm loss at 50 GHz, the loss can be reduced to 1.1 dB/cm loss at 50 GHz.

• International Journal of Oral Biology
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• v.44 no.2
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• pp.55-61
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• 2019

The purpose of this study was to evaluate the effect of mangosteen extract complex (MEC; Garcinia mangostana L. and propolis extracts) on the inhibition of inflammation and prevention of alveolar bone loss using a ligature-induced periodontitis model. Rat molars were ligatured with silk, and $1{\mu}g/mL$ of lipopolysaccharide of Porphyromonas gingivalis was injected into the buccal and palatal gingivae of the teeth with or without treatment with the MEC. Changes in the expression levels of prostaglandin $E_2$ ($PGE_2$), interleukin-8 (IL-8), inducible nitric oxide synthase (iNOS), matrix metalloproteinase-8 (MMP-8), cyclooxygenase (COX)-1, and COX-2 in gingival tissues were evaluated using enzyme-linked immunosorbent assays. Alveolar bone loss around the ligated molars was examined using micro-computed tomography. The expression levels of $PGE_2$, IL-8, iNOS, MMP-8, COX-1, and COX-2 in gingival tissues were significantly reduced in the group treated with a mixture of $16{\mu}g$ of mangosteen extract powder and $544{\mu}g$ of propolis extract powder (ligation [Lig] + lipopolysaccharide extracted from P. gingivalis KCOM 2804 [L] + MEC 1:34). Additionally, alveolar bone loss was significantly reduced in the Lig + L + MEC 1:34 group compared with that in other groups. These results indicate that the MEC could be useful in preventing and treating periodontitis.

• ETRI Journal
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• v.27 no.5
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• pp.639-642
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• 2005

This paper proposes two kinds of complexity-reduced algorithms for a low density parity check (LDPC) decoder. First, sequential decoding using a partial group is proposed. It has the same hardware complexity and requires a fewer number of iterations with little performance loss. The amount of performance loss can be determined by the designer, based on a tradeoff with the desired reduction in complexity. Second, an early detection method for reducing the computational complexity is proposed. Using a confidence criterion, some bit nodes and check node edges are detected early on during decoding. Once the edges are detected, no further iteration is required; thus early detection reduces the computational complexity.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.11
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• pp.167-170
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• 1995

An frequency modulated (FM) DANTE pulse sequence generates a quadratic phase toward the transverse of image by an FM RF pulse. In the image of a serious susceptibility effect, the phase due to the difference of the susceptibility in the pixel occurs susceptibility error which arise signal loss. But the signal loss due to the susceptibility effect in the pixel is reduced when the quadratic phase adds in the pixel. In this paper, we have generated a quadratic function toward the transverse (X-Y) using FM DANTE sequence and the susceptibility effect is reduced in the gradient echo (GE) imaging. Computer simulation and experimental results is obtained by using a whole-body KAIS 2.0T NMR system.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.239-242
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• 2005

A high speed address recovery technique for AC plasma display Panel(PDP) is proposed. By removing the GND switching operation, the recovery speed can be increased and switching loss due to GND switch also becomes to be reduced. The proposed method is able to perform load-adaptive operation by controlling the voltage level of energy recovery capacitor, which prevents increasing inefficient power consumption caused by circuit loss during recovery operation. Thus, the technique shows the minimum address power consumption according to various displayed images, different from Prior methods operating in fixed mode regardless of images. Test results with 50" HD single-scan PDP(resolution = 1366$\times$768) show that less than 350ns of recovery time is successfully accomplished and about 54% of the maximum power consumption can be reduced, tracing minimum power consumption curves.

• Journal of Society of Preventive Korean Medicine
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• v.7 no.1
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• pp.55-66
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• 2003

Osteoporosis is characterized by bone loss and mobidity with osteoporotic fracture. This study was performed to evaluate the effect of on the bone mass and its related factors in estrogen-deficient animal model. The model rats of osteoporsis showed a significant decrease in bone density, bone ash density, calcium content of femur bone. At the 14th day after ovariectomy-surgery, rats were administered with DBE, extract of Dioscorea batatas, per orally, and continued for 10 weeks. And osteoporosis related parameters were determined to investigate the effect of DBE. Osteoporetic rats showed lower serum estrogen level, higher body weight than normal rats, and showed atrophy of uterine horns. DBE showed inhibitory effect on bone loss in osteoporetic condition, and reduced the increase of ALP activity and osteocalcin level in serum, and reduced the increase of OH-proline level in urine. But, DBE had no effect on cell proliferation and ALP activity in rat calvarial cell culture.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.499-504
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• 2004

The purpose of this study is to investigate a investigating of a floor-impact isolation system using damping materials in apartment buildings. The stiffness elastic modulus(k) by puls impact forces were calculated loss factor by Hilbert transforms. It is absolved that natural frequency was moved floor shock-absorbing materials and the impact force was reduced by floor panel. The slab was constructed by damping materials. As towards a result, the system showed inverse A 45dB by heavy weight-impact noise and inverse A 52dB by light-impact noise. High frequencies impact-noise can be reduced by upgrading naturial frequency of vibration and noise in the system.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.4
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• pp.217-222
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• 2006

A distributed balun such as Marchand balun typically shows good phase and amplitude balances, but its size is somewhat large especially in lower frequency band. In contrast, a lumped balun has compact size but its performance is not good compared with that of a distributed one. In this paper the distributed-coupled line can be reduced effectively by using the lumped-distributed implementation. Designed balun has two coupled line of each ${\lambda}/72$ and shows magnitude balance of 0.05 dB, phase balance of $0.7^{\circ}$ in passband. Balanced-type filter is designed using balun and it has insertion loss of 8 dB, return loss of 7 dB, magnitude balance of 0.2 dB, and phase balance of $1.2^{\circ}$ in passband.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.05a
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• pp.192-200
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• 2005

A high speed address recovery technique for AC plasma display panel(PDP) is proposed. By removing the GND switching operation, the recovery speed can be increased and switching loss due to GND switch also becomes to be reduced. The proposed method is able to perform load-adaptive operation by controlling the voltage level of energy recovery capacitor, which prevents increasing inefficient power consumption caused by circuit loss during recovery operation. Thus, th e technique shows the minimum address power consumption according to various displayed images, different from prior methods operating in fixed mode regardless of images. Test results with 50' HD single- scan PDP(resolution : $1366{\times}768$) show that less than 350ns of recovery time is successfully accomplished and about $54\%$ of the maximum power consumption can be reduced, tracing minimum power consumption curves.

• Journal of Power Electronics
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• v.16 no.3
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• pp.894-904
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• 2016

This study examines the zero-voltage switching (ZVS) operation of an active-clamped forward converter (ACFC) with a current-doubler rectifier (CDR). The ZVS condition can be obtained with a much smaller leakage inductance compared to that of a conventional ACFC. Due to the significantly reduced leakage inductance, the design is optimized and the circulating loss is reduced. The operation of the ACFC with a CDR is analyzed, and a detailed ZVS analysis is conducted on the basis of a steady-state analysis. From the results, a design consideration for ZVS improvement is presented. Loss analyses of the converters shows that enhanced soft-switching contributes to an efficiency improvement under light-load condition. Experimental results from a 100-W (5-V/20-A) prototype verify that the ACFC with a CDR can attain ZVS across an extended load range of loads and achieve a higher efficiency than conventional ACFCs.